This project seeks to gain groundbreaking insights into an unresolved problem in biology that has vast importance to understand the molecular basis of cardiovascular disease: how specific DNA sequences are targeted for methylation. DNA methylation confers epigenetic control of gene expression in many organisms. Global alterations of DNA methylation are now widely recognized as a contributing factor in human cancer and cardiovascular. Despite the profound biological importance of DNA methylation, how particular DNA sequences are initially targeted for methylation remains largely unknown. We propose to address this question by investigating the mechanism of DRM2-mediated DNA methylation through the investigation of the role of DRM3, a catalytically inactive homology of DRM2, in targeting DRM2 to chromatin (Aim 1) and stimulating DRM2 methyltransferase catalytic activity (Aim 2). I will also identify new components that assist in DRM3 function by genetic screen (Aim 3). Completion of these studies will provide important new information about the molecular factors and interactions that recognize specific DNA sequences to initiate methylation. Because DNA methylation is highly conserved among plants and animals, results from this project are expected to help accelerate studies to understand the mechanisms of tumorigenesis and cardiovascular diseases caused by DNA methylation. PUBLIC HEALTH RELEVANCE: The human genome not only contains the basic genetic information for making a human body, but also contains "selfish DNAs" that function only to replicate themselves and their uncontrolled replication can cause cancers. The human body has a defense system to recognize and then add a special chemical mark, called methylation, on these DNAs to stop their replication. This project seeks to understand the molecular basis of how specific DNA sequences are recognized and targeted for methylation.